var createError = require('http-errors');
var express = require('express');
var path = require('path');
var cookieParser = require('cookie-parser');
var logger = require('morgan');
//1 引入代理服务器
const { createProxyMiddleware } = require('http-proxy-middleware');
//2 配置代理服务器
const options = {
  target: 'http://127.0.0.1:4000', // 代理的目标服务器
  changeOrigin: true, // 支持跨域
  pathRewrite: {
    '^/api/': '/', // 路径重写
  }
};

var app = express();

// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'jade');

//处理静态资源
app.use(express.static(path.join(__dirname, 'public')));
//3 创建代理服务器一定太要放在处理静态资源之后
// 处理路由资源之前
const proxy = createProxyMiddleware(options);
//4 注册代理服务器
app.use('/api', proxy);

// catch 404 and forward to error handler
app.use(function(req, res, next) {
  next(createError(404));
});

// error handler
app.use(function(err, req, res, next) {
  // set locals, only providing error in development
  res.locals.message = err.message;
  res.locals.error = req.app.get('env') === 'development' ? err : {};

  // render the error page
  res.status(err.status || 500);
  res.render('error');
});

module.exports = app;
